Functional characterization of flavobacteria rhodopsins reveals a unique class of light-driven chloride pump in bacteria
Name
Yoshizawa-2014-Functional character.pdf
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Author(s)
Yoshizawa, Susumu
Kumagai, Yohei
Kim, Hana
Ogura, Yoshitoshi
Hayashi, Tetsuya
Iwasaki, Wataru
DeLong, Edward
Kogure, Kazuhiro
Date Issued
March 2014
Journal
Proceedings of the National Academy of Sciences
Publisher
National Academy of Sciences (U.S.)
Citation
Yoshizawa, S., Y. Kumagai, H. Kim, Y. Ogura, T. Hayashi, W. Iwasaki, E. F. DeLong, and K. Kogure. “Functional Characterization of Flavobacteria Rhodopsins Reveals a Unique Class of Light-Driven Chloride Pump in Bacteria.” Proceedings of the National Academy of Sciences 111, no. 18 (March 31, 2014): 6732–6737.
Version
Final published version
Abstract
Light-activated, ion-pumping rhodopsins are broadly distributed among many different bacteria and archaea inhabiting the photic zone of aquatic environments. Bacterial proton- or sodium-translocating rhodopsins can convert light energy into a chemiosmotic force that can be converted into cellular biochemical energy, and thus represent a widespread alternative form of photoheterotrophy. Here we report that the genome of the marine flavobacterium Nonlabens marinus S1-08T encodes three different types of rhodopsins: Nonlabens marinus rhodopsin 1 (NM-R1), Nonlabens marinus rhodopsin 2 (NM-R2), and Nonlabens marinus rhodopsin 3 (NM-R3). Our functional analysis demonstrated that NM-R1 and NM-R2 are light-driven outward-translocating H+ and Na+ pumps, respectively. Functional analyses further revealed that the light-activated NM-R3 rhodopsin pumps Cl− ions into the cell, representing the first chloride-pumping rhodopsin uncovered in a marine bacterium. Phylogenetic analysis revealed that NM-R3 belongs to a distinct phylogenetic lineage quite distant from archaeal inward Cl−-pumping rhodopsins like halorhodopsin, suggesting that different types of chloride-pumping rhodopsins have evolved independently within marine bacterial lineages. Taken together, our data suggest that similar to haloarchaea, a considerable variety of rhodopsin types with different ion specificities have evolved in marine bacteria, with individual marine strains containing as many as three functionally different rhodopsins.
MIT Department
Massachusetts Institute of Technology. Department of Biological Engineering
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
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DOI of Published Version
https://doi.org/10.1073/pnas.1403051111
